The present invention relates to web presses in general, and to devices for cleaning a moving web in particular.
Paper is manufactured of fibers, typically of cellulose fibers made from wood. The fibers are formed into a sheet or web of paper which is pressed, dried, and wound onto a jumbo reel. Reels sized for printing newspaper are split from the jumbo reel and supplied to newspapers for printing.
A certain amount of dust, mainly loose cellulose fibers, is attached to the surfaces of the web as it is supplied to the presses, and this loose fiber tends to accumulate on roll surfaces and blankets within the press. In offset lithographic printing, the primary process used for newspaper printing, an oil-based ink is repelled from wetted portions of the printing plates. The cellulose fiber dust readily becomes wet and hence prevents ink from being properly applied to the paper. The buildup of loose fibers requires periodic cleaning of the press, reducing press availability and increasing the cost of press time.
Web cleaners have been developed to pre-clean paper. These cleaners include vacuum, air knife, and tack cleaners. One type of cleaner employs counter-rotating cleaning rolls which have stacks of canvas disks mounted on shafts and positioned on either side of the web to be cleaned. The rolls rotate counter to the direction the web is traveling and are positioned to create a boundary layer which penetrates the web boundary layer, to thereby strip off dust and fiber particles which are then removed by vacuum from the cleaning rolls. Web cleaners including rotating cleaners are relatively easily employed in presses designed for higher grades of printing such as magazines and books where the paper is fed into the press from front or back. Newspaper printing, however, will often utilize many webs, with each press typically having a web fed from beneath. The only suitable location for locating a web cleaner is above the press floor in the archway beneath the press. However, this space must be kept clear for threading the web, removal of inking rolls and access during a paper break.
What is needed is an apparatus for cleaning a web as it is fed from beneath a newsprint press.